1. Field of the Invention
The present invention relates to methods and systems for delivery of therapy to organ sites and to tumor sites in particular. More specifically, the present invention provides a new and improved systems and methods for delivering chemotherapy, gene therapy or other therapeutic agents to diseased or cancerous sites, and particularly to solid tumors.
2. Description of the Related Art
U.S. Pat. Nos. 4,714,460, 4,867,742 and 4,883,459, of each of which Applicant is inventor, relate to methods and systems for study and treatment in situ of tumors in a subject patient's body of retrograde perfusion. Although the techniques of retrograde perfusion have been considered as possibly advantageous and helpful, there has been hesitancy to attempt widespread experimentation using the techniques of these patents. There are also several problems still remaining which have hampered attempts in this area for treatment of tumors, regardless of the method or system proposed.
There has been an uncertainty or blind spot in the delivery procedure with respect to the path of travel or trajectory that a therapeutic agent travels during the infusion or treatment procedure. This has in turn caused a resultant unpredictability regarding the route(s) taken by a therapeutic agent once the agent has been administered by conventional intravenous delivery techniques.
Another problem has involved inadequate uptakes and nonoptimal distribution in tumors in vivo. As has been pointed out in Applicant's earlier U.S. patents: The tumor blood flow is thus impaired, measuring only two to fifteen percent of that of the surrounding tissue, and this impaired circulation distinguishes the cancer vasculature. The probability of blood flow through the V—V shunts is far less than the probability of blood flow through the normal vasculature. Therefore, in any attempt to deliver chemotherapy to a tumor, the likelihood that the drug will spread to the remainder of the body is far greater than the likelihood that it will reach the tumor. There were problems in making certain that the tumor (rather than the entire body) received a significantly high dose and duration of exposure to the treatment agent. Another problem was in determining and controlling the routes of drug delivery within a target site, as well as that of withdrawing any excess drug.
A final problem is isolation of the treatment agent to the area of the tumor in the patient. There are certain agents which have proven effective in chemotherapeutic treatment of tumors, but which have potentially severe side effects. An example is doxorubicin, available under the trademark ADRIAMYCIN®, which has been used as an anti-cancer drug for a number of years. That composition has been used to treat many forms of cancer including cancer of the breast and stomach, lymphoma and multiple myeloma. However, severe side effects have ensued. A common side effect if dosage is not controlled has been dilated cardiomyopathy. The use of this chemical to treat tumors has been limited, when systemically administered, due to its toxic side effect on the patient's heart.